Unable to see anything after importing .obj file
Imported objects from other file formats, are some times really small, off centered, or very far away from scene origin, compared to the default scene scale.
First step is to make sure anything was actually imported. Look in the Outliner for new objects under current collection (geometry should be of mesh type). If there are any, use the outliner to select them.

Then with the mouse over the 3D View press the Numpad . (Period) key, or go to View &gt; Frame Selected for 2.8+, to view selected objects.
This will zoom in tightly on the selected object.